(1) Field of the Invention
The present invention relates to a pin-tucking sewing machine exclusively used for providing pin-tucking. A pin-tucking sewing machine comprises a plurality of sewing needles arranged equidistantly. The fabric material or cloth is folded along a corresponding number of pin-tuck lines extending in parallel and equidistantly. Thus continuously folded pin-tucking are sewn by the plurality of needles arranged in a row extending in normal to the moving direction of the fabric material to form decorative stitch lines.
More especially, the present invention relates to the guide board used for guiding the fabric material to form the pin-tucking folds and to feed to the needle plate.
(2) Description of the Prior Art
The abovementioned pin-tucking sewing machine had been used in practice. The known pin-tucking sewing machine comprises a pair of guide boards, i.e. an upper guide board and a lower guide board. A fabric material to be worked is passed through the pair of guide boards and is folded along a number of pin-tucking lines extending in parallel and equidistantly. The fabric is continuously folded and sewn by the plurality of needles provided in a corresponding number with the stitch lines to form pin-tucking. The needles are arranged at even interval and at location the fabric material is fed out.
FIGS. 7 and 8 show a pair of such known guide boards. FIG. 7 shows an upper guide board 20 and FIG. 8 shows a lower guide board 21. The two guide boards 20 and 21 are used in stucked position with each other. Each of the guide board 20 or 21 comprises a certain number of guide members 26 extending from the surface. The guide members 26 have radially extending guide portion 25 and parallel working heads 24 extending in parallel and equidistantly. The working heads 24 terminate at the ends with tucking guide 22 or 23. In the prior art construction, the guide members 26 are fixedly mounted on the base of the guide board 20 or 21 for instance by welding.
Accordingly, in the prior art machine, the width of the tucked portion and the space thereof or the space of the stitches are uniformly decided previously by the guide boards used for the machine.
FIG. 9 shows one embodiment of the finished fabric obtained by the prior art pin-tucking sewing machine. In FIG. 9, "B" shows the fabric material to be worked and "C" is the pin-tucking. In the prior art machine, only such uniformly spaced pin-tucking has been obtained unless the guide board itself is interchanged. FIG. 9 shows in case of 12 pin-tucking obtained by 12 parallel sewing needles. In case if the width of the pin-tucking or the space therebetween is desired to be widened, the corresponding thread on the stitch once sewn must be removed after completing the even spaced pin-tucking, for instance, 12 pin-tucking. In this case, the surface of the fabric material is spoiled by the needle at which the stitch is to be removed. This spoils outer looking of the completed fabric. More especially in case if the fabric material is cotton, the stitches once sews or even folded tuckings are very difficult to be removed by ironing or the like.